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x509asn1: always check return code from getASN1Element()
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bagder committed Oct 24, 2018
1 parent 9ddf92c commit 346dd5e
Showing 1 changed file with 102 additions and 32 deletions.
134 changes: 102 additions & 32 deletions lib/x509asn1.c
Expand Up @@ -103,6 +103,9 @@ static const curl_OID OIDtable[] = {
* Please note there is no pretention here to rewrite a full SSL library.
*/

static const char *getASN1Element(curl_asn1Element *elem,
const char *beg, const char *end)
WARN_UNUSED_RESULT;

static const char *getASN1Element(curl_asn1Element *elem,
const char *beg, const char *end)
Expand Down Expand Up @@ -602,10 +605,17 @@ static ssize_t encodeDN(char *buf, size_t n, curl_asn1Element *dn)

for(p1 = dn->beg; p1 < dn->end;) {
p1 = getASN1Element(&rdn, p1, dn->end);
if(!p1)
return -1;
for(p2 = rdn.beg; p2 < rdn.end;) {
p2 = getASN1Element(&atv, p2, rdn.end);
if(!p2)
return -1;
p3 = getASN1Element(&oid, atv.beg, atv.end);
getASN1Element(&value, p3, atv.end);
if(!p3)
return -1;
if(!getASN1Element(&value, p3, atv.end))
return -1;
str = ASN1tostr(&oid, 0);
if(!str)
return -1;
Expand Down Expand Up @@ -697,10 +707,15 @@ int Curl_parseX509(curl_X509certificate *cert,

/* Get tbsCertificate. */
beg = getASN1Element(&tbsCertificate, beg, end);
if(!beg)
return -1;
/* Skip the signatureAlgorithm. */
beg = getASN1Element(&cert->signatureAlgorithm, beg, end);
if(!beg)
return -1;
/* Get the signatureValue. */
getASN1Element(&cert->signature, beg, end);
if(!getASN1Element(&cert->signature, beg, end))
return -1;

/* Parse TBSCertificate. */
beg = tbsCertificate.beg;
Expand All @@ -710,28 +725,47 @@ int Curl_parseX509(curl_X509certificate *cert,
cert->version.beg = &defaultVersion;
cert->version.end = &defaultVersion + sizeof(defaultVersion);
beg = getASN1Element(&elem, beg, end);
if(!beg)
return -1;
if(elem.tag == 0) {
getASN1Element(&cert->version, elem.beg, elem.end);
if(!getASN1Element(&cert->version, elem.beg, elem.end))
return -1;
beg = getASN1Element(&elem, beg, end);
if(!beg)
return -1;
}
cert->serialNumber = elem;
/* Get signature algorithm. */
beg = getASN1Element(&cert->signatureAlgorithm, beg, end);
/* Get issuer. */
beg = getASN1Element(&cert->issuer, beg, end);
if(!beg)
return -1;
/* Get notBefore and notAfter. */
beg = getASN1Element(&elem, beg, end);
if(!beg)
return -1;
ccp = getASN1Element(&cert->notBefore, elem.beg, elem.end);
getASN1Element(&cert->notAfter, ccp, elem.end);
if(!ccp)
return -1;
if(!getASN1Element(&cert->notAfter, ccp, elem.end))
return -1;
/* Get subject. */
beg = getASN1Element(&cert->subject, beg, end);
if(!beg)
return -1;
/* Get subjectPublicKeyAlgorithm and subjectPublicKey. */
beg = getASN1Element(&cert->subjectPublicKeyInfo, beg, end);
if(!beg)
return -1;
ccp = getASN1Element(&cert->subjectPublicKeyAlgorithm,
cert->subjectPublicKeyInfo.beg,
cert->subjectPublicKeyInfo.end);
getASN1Element(&cert->subjectPublicKey, ccp,
cert->subjectPublicKeyInfo.end);
cert->subjectPublicKeyInfo.beg,
cert->subjectPublicKeyInfo.end);
if(!ccp)
return -1;
if(!getASN1Element(&cert->subjectPublicKey, ccp,
cert->subjectPublicKeyInfo.end))
return -1;
/* Get optional issuerUiqueID, subjectUniqueID and extensions. */
cert->issuerUniqueID.tag = cert->subjectUniqueID.tag = 0;
cert->extensions.tag = elem.tag = 0;
Expand All @@ -740,20 +774,30 @@ int Curl_parseX509(curl_X509certificate *cert,
cert->subjectUniqueID.beg = cert->subjectUniqueID.end = "";
cert->extensions.header = NULL;
cert->extensions.beg = cert->extensions.end = "";
if(beg < end)
if(beg < end) {
beg = getASN1Element(&elem, beg, end);
if(!beg)
return -1;
}
if(elem.tag == 1) {
cert->issuerUniqueID = elem;
if(beg < end)
if(beg < end) {
beg = getASN1Element(&elem, beg, end);
if(!beg)
return -1;
}
}
if(elem.tag == 2) {
cert->subjectUniqueID = elem;
if(beg < end)
if(beg < end) {
beg = getASN1Element(&elem, beg, end);
if(!beg)
return -1;
}
}
if(elem.tag == 3)
getASN1Element(&cert->extensions, elem.beg, elem.end);
if(!getASN1Element(&cert->extensions, elem.beg, elem.end))
return -1;
return 0;
}

Expand Down Expand Up @@ -782,11 +826,14 @@ static const char *dumpAlgo(curl_asn1Element *param,
/* Get algorithm parameters and return algorithm name. */

beg = getASN1Element(&oid, beg, end);
if(!beg)
return NULL;
param->header = NULL;
param->tag = 0;
param->beg = param->end = end;
if(beg < end)
getASN1Element(param, beg, end);
if(!getASN1Element(param, beg, end))
return NULL;
return OID2str(oid.beg, oid.end, TRUE);
}

Expand Down Expand Up @@ -821,10 +868,14 @@ static void do_pubkey(struct Curl_easy *data, int certnum,
/* Generate all information records for the public key. */

/* Get the public key (single element). */
getASN1Element(&pk, pubkey->beg + 1, pubkey->end);
if(!getASN1Element(&pk, pubkey->beg + 1, pubkey->end))
return;

if(strcasecompare(algo, "rsaEncryption")) {
p = getASN1Element(&elem, pk.beg, pk.end);
if(!p)
return;

/* Compute key length. */
for(q = elem.beg; !*q && q < elem.end; q++)
;
Expand All @@ -845,30 +896,34 @@ static void do_pubkey(struct Curl_easy *data, int certnum,
}
/* Generate coefficients. */
do_pubkey_field(data, certnum, "rsa(n)", &elem);
getASN1Element(&elem, p, pk.end);
if(!getASN1Element(&elem, p, pk.end))
return;
do_pubkey_field(data, certnum, "rsa(e)", &elem);
}
else if(strcasecompare(algo, "dsa")) {
p = getASN1Element(&elem, param->beg, param->end);
do_pubkey_field(data, certnum, "dsa(p)", &elem);
p = getASN1Element(&elem, p, param->end);
do_pubkey_field(data, certnum, "dsa(q)", &elem);
getASN1Element(&elem, p, param->end);
do_pubkey_field(data, certnum, "dsa(g)", &elem);
do_pubkey_field(data, certnum, "dsa(pub_key)", &pk);
if(p) {
do_pubkey_field(data, certnum, "dsa(p)", &elem);
p = getASN1Element(&elem, p, param->end);
if(p) {
do_pubkey_field(data, certnum, "dsa(q)", &elem);
if(getASN1Element(&elem, p, param->end)) {
do_pubkey_field(data, certnum, "dsa(g)", &elem);
do_pubkey_field(data, certnum, "dsa(pub_key)", &pk);
}
}
}
}
else if(strcasecompare(algo, "dhpublicnumber")) {
p = getASN1Element(&elem, param->beg, param->end);
do_pubkey_field(data, certnum, "dh(p)", &elem);
getASN1Element(&elem, param->beg, param->end);
do_pubkey_field(data, certnum, "dh(g)", &elem);
do_pubkey_field(data, certnum, "dh(pub_key)", &pk);
}
#if 0 /* Patent-encumbered. */
else if(strcasecompare(algo, "ecPublicKey")) {
/* Left TODO. */
if(p) {
do_pubkey_field(data, certnum, "dh(p)", &elem);
if(getASN1Element(&elem, param->beg, param->end)) {
do_pubkey_field(data, certnum, "dh(g)", &elem);
do_pubkey_field(data, certnum, "dh(pub_key)", &pk);
}
}
}
#endif
}

CURLcode Curl_extract_certinfo(struct connectdata *conn,
Expand Down Expand Up @@ -1107,18 +1162,29 @@ CURLcode Curl_verifyhost(struct connectdata *conn,
/* Process extensions. */
for(p = cert.extensions.beg; p < cert.extensions.end && matched != 1;) {
p = getASN1Element(&ext, p, cert.extensions.end);
if(!p)
return CURLE_PEER_FAILED_VERIFICATION;

/* Check if extension is a subjectAlternativeName. */
ext.beg = checkOID(ext.beg, ext.end, sanOID);
if(ext.beg) {
ext.beg = getASN1Element(&elem, ext.beg, ext.end);
if(!ext.beg)
return CURLE_PEER_FAILED_VERIFICATION;
/* Skip critical if present. */
if(elem.tag == CURL_ASN1_BOOLEAN)
if(elem.tag == CURL_ASN1_BOOLEAN) {
ext.beg = getASN1Element(&elem, ext.beg, ext.end);
if(!ext.beg)
return CURLE_PEER_FAILED_VERIFICATION;
}
/* Parse the octet string contents: is a single sequence. */
getASN1Element(&elem, elem.beg, elem.end);
if(!getASN1Element(&elem, elem.beg, elem.end))
return CURLE_PEER_FAILED_VERIFICATION;
/* Check all GeneralNames. */
for(q = elem.beg; matched != 1 && q < elem.end;) {
q = getASN1Element(&name, q, elem.end);
if(!q)
break;
switch(name.tag) {
case 2: /* DNS name. */
len = utf8asn1str(&dnsname, CURL_ASN1_IA5_STRING,
Expand Down Expand Up @@ -1159,8 +1225,12 @@ CURLcode Curl_verifyhost(struct connectdata *conn,
distinguished one to get the most significant one. */
while(q < cert.subject.end) {
q = getASN1Element(&dn, q, cert.subject.end);
if(!q)
break;
for(p = dn.beg; p < dn.end;) {
p = getASN1Element(&elem, p, dn.end);
if(!p)
return CURLE_PEER_FAILED_VERIFICATION;
/* We have a DN's AttributeTypeAndValue: check it in case it's a CN. */
elem.beg = checkOID(elem.beg, elem.end, cnOID);
if(elem.beg)
Expand Down

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